Economics · Ch 2 — Theory of Consumer Behaviour
Utility
Utility
Utility – The Want-Satisfying Capacity of a Commodity
A consumer’s decision to demand a particular commodity is driven by the satisfaction — or utility — they expect to get from it. Utility is defined as the want-satisfying capacity of a commodity. In other words, a commodity has utility if it can fulfil some human want, whether that want is basic (like food) or a matter of taste (like a chocolate).
The strength of the desire for a commodity determines the level of utility it provides. The more urgently a person needs a commodity, or the stronger their desire to have it, the greater the utility they derive from it. For example, a thirsty person in a desert gets enormous utility from a glass of water, while the same glass of water gives very little utility to someone who has just drunk two litres.
Utility is Subjective
A critical point: utility is subjective — it varies from person to person. Two individuals can get completely different levels of utility from the same commodity. The textbook gives a clear example: someone who loves chocolates will get much higher utility from a chocolate than someone who is not fond of chocolates. This subjectivity is why economists cannot measure utility in absolute, objective units like kilograms or metres; it is a personal, psychological experience.
Because utility is subjective, we cannot compare the utility one person gets from a commodity with the utility another person gets from the same commodity. There is no common scale. This is why early economists (like Alfred Marshall) assumed utility could be measured in imaginary units called ‘utils’, but modern theory avoids such direct comparisons.
Utility Changes with Place and Time
Utility is not fixed even for the same individual. It can change with place and time. The textbook gives a concrete illustration: the utility from using a room heater depends on whether the individual is in Ladakh (a cold region) or Chennai (a hot coastal city) — that is the place factor. It also depends on whether it is summer or winter — that is the time factor. A heater gives high utility in a Ladakh winter but almost zero utility in a Chennai summer.
This variability is important because it means that a consumer’s demand for a commodity is not constant; it shifts with circumstances. A good that is highly useful in one situation may be useless in another.
A common mistake is to think that utility is the same as ‘usefulness’ in an objective sense. A medicine may be objectively useful, but if a person does not need it (e.g., they are healthy), its utility for them is low. Utility is always about the individual’s subjective want at that moment.